sleuth: [12] Sleuth originally meant ‘track, trail’ (‘John of Lorn perceived the hound had lost the sleuth’, John Barbour, The Bruce 1375). It was borrowed from Old Norse slóth ‘track, trail’, which was probably also the ultimate source of English slot ‘trail of an animal’ [16]. In the 14th century the compound sleuth-hound ‘bloodhound for tracking fugitives’ was coined. This was later shortened back to sleuth, and applied in 19th-century America to a ‘detective’. => slot[sleuth etymology, sleuth origin, 英语词源]